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libcxx/test/std/containers/views/span.sub/first.pass.cpp

137 lines
4.0 KiB
C++

// -*- C++ -*-
//===------------------------------ span ---------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===---------------------------------------------------------------------===//
// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
// <span>
// template<ptrdiff_t Count>
// constexpr span<element_type, Count> first() const;
//
// constexpr span<element_type, dynamic_extent> first(index_type count) const;
//
// Requires: 0 <= Count && Count <= size().
#include <span>
#include <cassert>
#include <algorithm>
#include <string>
#include "test_macros.h"
template <typename Span, ptrdiff_t Count>
constexpr bool testConstexprSpan(Span sp)
{
LIBCPP_ASSERT((noexcept(sp.template first<Count>())));
LIBCPP_ASSERT((noexcept(sp.first(Count))));
auto s1 = sp.template first<Count>();
auto s2 = sp.first(Count);
using S1 = decltype(s1);
using S2 = decltype(s2);
ASSERT_SAME_TYPE(typename Span::value_type, typename S1::value_type);
ASSERT_SAME_TYPE(typename Span::value_type, typename S2::value_type);
static_assert(S1::extent == Count, "");
static_assert(S2::extent == std::dynamic_extent, "");
return
s1.data() == s2.data()
&& s1.size() == s2.size()
&& std::equal(s1.begin(), s1.end(), sp.begin());
}
template <typename Span, ptrdiff_t Count>
void testRuntimeSpan(Span sp)
{
LIBCPP_ASSERT((noexcept(sp.template first<Count>())));
LIBCPP_ASSERT((noexcept(sp.first(Count))));
auto s1 = sp.template first<Count>();
auto s2 = sp.first(Count);
using S1 = decltype(s1);
using S2 = decltype(s2);
ASSERT_SAME_TYPE(typename Span::value_type, typename S1::value_type);
ASSERT_SAME_TYPE(typename Span::value_type, typename S2::value_type);
static_assert(S1::extent == Count, "");
static_assert(S2::extent == std::dynamic_extent, "");
assert(s1.data() == s2.data());
assert(s1.size() == s2.size());
assert(std::equal(s1.begin(), s1.end(), sp.begin()));
}
constexpr int carr1[] = {1,2,3,4};
int arr[] = {5,6,7};
std::string sarr [] = { "ABC", "DEF", "GHI", "JKL", "MNO"};
int main ()
{
{
using Sp = std::span<const int>;
static_assert(testConstexprSpan<Sp, 0>(Sp{}), "");
static_assert(testConstexprSpan<Sp, 0>(Sp{carr1}), "");
static_assert(testConstexprSpan<Sp, 1>(Sp{carr1}), "");
static_assert(testConstexprSpan<Sp, 2>(Sp{carr1}), "");
static_assert(testConstexprSpan<Sp, 3>(Sp{carr1}), "");
static_assert(testConstexprSpan<Sp, 4>(Sp{carr1}), "");
}
{
using Sp = std::span<const int, 4>;
static_assert(testConstexprSpan<Sp, 0>(Sp{carr1}), "");
static_assert(testConstexprSpan<Sp, 1>(Sp{carr1}), "");
static_assert(testConstexprSpan<Sp, 2>(Sp{carr1}), "");
static_assert(testConstexprSpan<Sp, 3>(Sp{carr1}), "");
static_assert(testConstexprSpan<Sp, 4>(Sp{carr1}), "");
}
{
using Sp = std::span<int>;
testRuntimeSpan<Sp, 0>(Sp{});
testRuntimeSpan<Sp, 0>(Sp{arr});
testRuntimeSpan<Sp, 1>(Sp{arr});
testRuntimeSpan<Sp, 2>(Sp{arr});
testRuntimeSpan<Sp, 3>(Sp{arr});
}
{
using Sp = std::span<int, 3>;
testRuntimeSpan<Sp, 0>(Sp{arr});
testRuntimeSpan<Sp, 1>(Sp{arr});
testRuntimeSpan<Sp, 2>(Sp{arr});
testRuntimeSpan<Sp, 3>(Sp{arr});
}
{
using Sp = std::span<std::string>;
testConstexprSpan<Sp, 0>(Sp{});
testRuntimeSpan<Sp, 0>(Sp{sarr});
testRuntimeSpan<Sp, 1>(Sp{sarr});
testRuntimeSpan<Sp, 2>(Sp{sarr});
testRuntimeSpan<Sp, 3>(Sp{sarr});
testRuntimeSpan<Sp, 4>(Sp{sarr});
testRuntimeSpan<Sp, 5>(Sp{sarr});
}
{
using Sp = std::span<std::string, 5>;
testRuntimeSpan<Sp, 0>(Sp{sarr});
testRuntimeSpan<Sp, 1>(Sp{sarr});
testRuntimeSpan<Sp, 2>(Sp{sarr});
testRuntimeSpan<Sp, 3>(Sp{sarr});
testRuntimeSpan<Sp, 4>(Sp{sarr});
testRuntimeSpan<Sp, 5>(Sp{sarr});
}
}